Wheel lift apparatus for towing vehicles

Abstract

A wheel lift towing apparatus is disclosed for mounting on the rear end of a tow truck or other towing vehicle for engaging the wheels of an immobilized vehicle to be towed. A rearwardly extending boom assembly is mounted at the rear end of the tow truck. Wheel lift carriages are mounted on the free end of the boom assembly for engaging the wheels of the immobilized vehicle for lifting the vehicle. An inclined ramp and follower mechanism is provided between a mounting bracket on the tow truck and the boom assembly for guiding upward lifting movement of the boom assembly and for effecting angular upward movement of the wheel lift carriages greater than the upper movement of the forward end of the boom assembly. Each wheel lift carriage is in the form of a fork-like structure having a pair of arms positionable on the inner and outer sides of a wheel. The inner arm has an aperture for insertion thereinto of the inner end of the support rod. The outer arm has an upwardly opening notch for insertion thereinto of the outer end of the support rod in a direction generally transversely of the arm.

I claim: 
     
       1. A wheel lift towing apparatus for the rear end of a tow truck or other towing vehicle for engaging the wheels of a vehicle to be towed, comprising: means for mounting the apparatus at the rear end of the tow truck;   boom means extending rearwardly of the mounting means;   carriage means on the rear end of the boom means for engaging the wheels of the vehicle to be towed and for lifting the vehicle; and   complementary interengaging means between the mounting means and the front end of the boom means for guiding upward lifting movement of the boom means relative to the mounting means and for effecting angular upward movement of the rear end of the boom means and the carriage means greater than the upward movement of the forward end of the boom means, said complementary interengaging means including forwardly inclined, upwardly extending ramp means on said mounting means, the ramp means being of generally uniform cross section along the length thereof and being defined by a pair of inwardly opening parallel slots, a generally vertical post member of generally uniform cross section disposed at the front end of the boom means, a pair of follower rollers mounted directly to the upper end of the post member, one of said roller members being engageable within each of said inwardly opening slots for riding upwardly therealong and said rollers defining the pivot axis of the post member, and fixed fulcrum means on the mounting means at the base of the inclined ramp means for bearing against the front side of said vertical post member of the boom means, whereby angular upward tilting movement of the boom means is effected in response to said relative upward lifting movement of the boom means with said rollers defining both the upward guide means for the boom and the pivot point for the boom.   
     
     
       2. The apparatus of claim 1 wherein said fixed fulcrum means comprises a roller. 
     
     
       3. The apparatus of claim 1 wherein said carriage means includes at least one fork-like structure having a pair of arms positionable on the inner and outer sides of a wheel, the inner arm having aperture means for the insertion thereinto of an inner end of a wheel support rod, and the outer arm having notch means for the insertion thereinto of the outer end of the wheel support rod in a direction generally transversely of the arm, said notch means comprising a generally L-shaped notch having a vertical leg portion for receiving the wheel support rod downwardly thereinto and a horizontal leg portion for locking the wheel support rod against vertical movement. 
     
     
       4. A lifting apparatus for a tow truck or other towing vehicle for engaging and lifting a vehicle to be towed, comprising: means for mounting the apparatus on the tow truck;   boom means extending rearwardly of the mounting means and including means for engaging the vehicle; and   complementary interengaging means between the mounting means and the front end of the boom means for guiding upward lifting movement of the boom means relative to the mounting means and for effecting angular upward movement of the free end of the boom means greater than the upward movement of the front end of the boom means, said complementary interengaging means including forwardly inclined, upwardly extending ramp means on said mounting means, the ramp means being of generally uniform cross section along the length thereof and being defined by a pair of inwardly opening parallel slots, a generally vertical post member of generally uniform cross section disposed at the front end of the boom means, a pair of follower rollers mounted directly to the upper end of the post member, one of said roller members being engageable within each of said inwardly opening slots for riding upwardly therealong and said rollers defining the pivot axis of the post member, and fixed fulcrum means on the mounting means at the base of the inclined ramp means for bearing against the front side of said vertical post member of the boom means, whereby angular upward tilting movement of the boom means is effected in response to said relative upward lifting movement of the boom means with said rollers defining both the upward guide means for the boom and the pivot point for the boom.   
     
     
       5. The apparatus of claim 4 wherein said fixed fulcrum means comprises a roller. 
     
     
       6. The apparatus of claim 4 including a carriage means which includes at least one fork-like structure having a pair of arms positionable on the inner and outer sides of a wheel, the inner arm having aperture means for the insertion thereinto of an inner end of a wheel support rod, and the outer arm having notch means for the insertion thereinto of the outer end of the wheel support rod in a direction generally transversely of the arm, said notch means comprising a generally L-shaped notch having a vertical leg portion for receiving the wheel support rod downwardly thereinto and a horizontal leg portion for locking the wheel support rod against vertical movement. 
     
     
       7. In a wheel lift towing apparatus for the rear end of a tow truck or other towing vehicle for engaging the wheels of a vehicle to be towed, the apparatus including boom means extending rearwardly of the towing vehicle, and carriage means on the free end of the boom means for engaging the wheels of the vehicle to be towed and for lifting the vehicle, an improvement in said carriage means comprising at least one fork-like structure having a pair of arms positionable on the inner and outer sides of a wheel, the inner arm having aperture means for the insertion thereinto of an inner end of a wheel support rod, and the outer arm having notch means for the insertion thereinto of the outer end of the wheel support rod in a direction generally transversely of the arm, said notch means comprising a generally L-shaped notch having a vertical leg portion for receiving the wheel support rod downwardly thereinto and a horizontal leg portion for locking the wheel support rod against vertical movement. 
     
     
       8. The improvement of claim 7 wherein said notch means is formed in the upper edge of the outer arm of the carriage means. 
     
     
       9. The improvement of claim 7, including a plurality of said notches spaced along the upper edge of the outer arm of the carriage means aligned with a plurality of apertures in the inner arm. 
     
     
       10. In a wheel lift towing apparatus for the rear end of a tow truck or other towing vehicle for engaging the wheels of a vehicle to be towed, the apparatus including boom means extending rearwardly of the towing vehicle, and carriage means on the free end of the boom means for engaging the wheels of the vehicle to be towed and for lifting the vehicle, an improvement in said carriage means comprising at least one fork-like structure having a pair of arms positionable on the inner and outer sides of a wheel, the outer arm having notch means for the insertion thereinto of a wheel engaging member in a direction transversely of the arm, said notch means comprising a generally L-shaped notch having a vertical leg portion for receiving the wheel engaging member downwardly thereinto and a horizontal leg portion for locking the wheel engaging member against vertical movement. 
     
     
       11. The improvement of claim 10 wherein said notch means is formed in the upper edge of the outer arm of the carriage means. 
     
     
       12. The improvement of claim 10, including a plurality of said notches along the upper edge of the outer arm of the carriage means.